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Canada’s docile ‘living fossil’ can’t handle the heat

The Wild Side, Part Two: As the human footprint expands across Canada, so does the threat to the country’s wildlife. There are now 650 species officially listed as endangered, threatened, special concern, or no longer found in the wild in Canada. In part two of the series, Postmedia News looks at a small mammal scientists refer to as “a living fossil.”

The Mountain Beaver, shown here after being caught by BC researchers, is the most primitive rodent alive in the world today. Photo by Michelle Holst

Fresh green ferns and leaves stacked up at the entrance of the tunnel are a dead giveaway. The “living fossil” is in.

But good luck seeing the creature, which is known as the Mountain Beaver.

It is so elusive that homeowners near colonies on mountain slopes outside Vancouver are often unaware that the strange little mammals are nibbling on carrots in their backyards.

“They’d have no idea,” says wildlife biologist Pontus Lindgren, who studied one colony that had been raiding gardens.

While the creatures share a name with the much more common North American Beaver, that is pretty much where the similarities end.

Mountain Beavers are, as scientists put it, a “living fossil.” They are the most primitive rodent alive in the world today, the only remaining representative of a family of creatures that dates back at least 25 million years, long before humans walked the Earth.

Once widespread across North America, they took refuge in the cool, moist forests of the Pacific Northwest as the climate changed over the eons. The only surviving population now lives in a strip running from California up into the southern tip of British Columbia.

“They have tiny distribution – that’s it in the world,” says biologist Les Gyug, of Okanagan Wildlife Consulting, who co-authored a new report on mountain beaver for the Committee on the Status of Endangered Wildlife in Canada, or COSEWIC, a national body that assesses species at risk.

Like many species in this country, the beavers are at the northern edge of their range in Canada and increasingly hemmed in by human activities. Logging equipment compacts the soil the beavers use for their underground burrows; agriculture has chased them out of the Fraser Valley; urban sprawl is eating away at mountainside habitat; and climate change is a looming threat.

“Canada’s other beaver can’t handle the heat,” COSEWIC noted in releasing the new report on the ancient rodent that it first assesed as a species of special concern in 1999.

The report says the mountain beaver – which has long been treated as vermin in the U.S. – should remain federally listed as a species of special concern in Canada. It’s up to the federal Environment Minister Peter Kent, who recently decided not to confer this status on three other obscure species which are common in the U.S., to decide whether to take COSEWIC’s advice.

It’s not known how many mountain beavers exist in Canada – COSEWIC’s “coarse” estimate, based on more than a decade of forest surveys, is that there are more than 10,000 in the southwest corner of B.C. But it says their range has shrunk by almost 30 per cent in the last 50 years, largely due to habitat loss.

Gyug says forestry remains the creature’s biggest threat.

B.C. loggers are no longer allowed to run heavy equipment within five metres of streams. But Gyug says close to 80 per cent of the beaver burrows are more than five metres away from streams and at the mercy of bulldozers and compactors that clear forests.

He says the B.C. government could do much to help the beavers by adding them to the list of “Identified wildlife” under its forestry regulations, which would require companies to tread more lightly around the burrows. The media office at the B.C. environment ministry had no comment about why the mountain beaver is not on the list.

Once clear-cuts start to grow back, Gyug says the beavers tend to do well, feeding on ferns and succulent plants growing amongst young trees.

Closer to Vancouver, urban sprawl is the big threat, says Lindgren, senior biologist with Madrone Environmental Services Ltd., who has helped chart the retreat of colonies up the Fraser Valley. New housing developments are eating into forested slopes – and adding domestic pets into the mix.

“Cats and dogs might be a death sentence, we don’t really know,” says Lindgren, noting how the beavers are not exactly swift on their feet. “They are very docile,“ he says.